1. To determine the extent of immunoglobulin gene rearrangements on the expressed chromosome and the nonexpressed homologous chromosome in allelically excluded normal B lymphocytes. 2. To identify the earliest stage of B cell differentiation wherein immunoglobulin gene rearrangements occur. 3. To determine whether somatic diversification occurs within a particular V region family to expand the number of possible sequences expressed during normal B lymphocyte and plasma cell differentiation.